Method And Apparatus For Making Disposable Absorbent Article With Absorbent Particulate Polymer Material And Article Made Therewith

ABSTRACT

A method for making a disposable absorbent core comprises depositing absorbent particulate polymer material from a plurality of reservoirs in a printing roll onto a substrate disposed on a grid of a support which includes a plurality of cross bars extending substantially parallel to and spaced from one another so as to form channels extending between the plurality of cross bars. The plurality of reservoirs in the first peripheral surface are arranged in an array comprising rows extending substantially parallel to and spaced from one another. The support and printing roll are arranged such that the plurality of cross bars are substantially parallel to the rows of the plurality of reservoirs and the absorbent particulate polymer material is deposited on the substrate in a pattern such that the absorbent particulate polymer material collects in rows on the first substrate formed between the first plurality of cross bars. A thermoplastic adhesive material is deposited on the absorbent particulate polymer material and the substrate to cover the absorbent particulate polymer material on the substrate and form an absorbent layer. A disposable absorbent article and apparatus for making an absorbent article are also disclosed.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.61/091,799, filed Aug. 26, 2008.

FIELD OF THE INVENTION

The present invention generally relates to an absorbent article and amethod and apparatus for making an absorbent article, and moreparticularly to a method and apparatus for making a disposable absorbentarticle with absorbent particulate polymer material, such as a diaper.

BACKGROUND OF THE INVENTION

Absorbent articles, such as disposable diapers, training pants, andadult incontinence undergarments, absorb and contain body exudates. Theyalso are intended to prevent body exudates from soiling, wetting, orotherwise contaminating clothing or other articles, such as bedding,that come in contact with the wearer. A disposable absorbent article,such as a disposable diaper, may be worn for several hours in a drystate or in a urine loaded state. Accordingly, efforts have been madetoward improving the fit and comfort of the absorbent article to thewearer, both when the article is dry and when the article is fully orpartially loaded with liquid exudate, while maintaining or enhancing theabsorbing and containing functions of the article.

Some absorbent articles, like diapers, contain an absorbent polymermaterial (also known as super absorbent polymer), such as an absorbentparticulate polymer material. Absorbent particulate polymer materialabsorbs liquid and swells and may be more effective when disposed in anabsorbent article in a certain pattern or arrangement intended foroptimal absorbency, fit, and/or comfort. Thus, it may be desirable forabsorbent particulate polymer material to remain in its intendedlocation in an absorbent article and absorbent particulate polymermaterial, therefore, is desirably immobilized in the absorbent articlesuch that the absorbent particulate polymer material remains immobilizedwhen the absorbent article is dry and when it is wet.

In addition to being absorbent, absorbent articles, such as diapers, maydesirably be thin and flexible, for ease and comfort in use and for moreconvenient and neat packaging and storage. Absorbent articles, which mayoften be used in large quantities, may also desirably be inexpensive.Some technologies of immobilizing absorbent particulate polymer materialin an absorbent article add bulk to the absorbent article and therebyincrease thickness, reduce flexibility, and/or increase cost of theabsorbent article. Other technologies for immobilizing absorbentparticulate polymer material in an absorbent article may not be aseffective in maintaining immobilization when the absorbent article is inthe wet state as when in the dry state. Accordingly, there remains aneed for a thin, flexible, and/or inexpensive absorbent articlecontaining absorbent particulate polymer material with enhancedimmobilization of the absorbent particulate polymer material in thearticle in dry and wet states.

SUMMARY OF THE INVENTION

The present invention addresses one or more technical problems describedabove and provides a method for making a disposable absorbent articlewhich may comprise depositing absorbent particulate polymer materialfrom a plurality of reservoirs in a printing roll onto a substratedisposed on a grid of a support which includes a plurality of cross barsextending substantially parallel to and spaced from one another so as toform channels extending between the plurality of cross bars. Theplurality of reservoirs in the first peripheral surface may be arrangedin an array comprising rows extending substantially parallel to andspaced from one another. The support and printing roll may be arrangedsuch that the plurality of cross bars are substantially parallel to therows of the plurality of reservoirs and the absorbent particulatepolymer material is deposited on the substrate in a pattern such thatthe absorbent particulate polymer material collects in rows on the firstsubstrate formed between the first plurality of cross bars. Athermoplastic adhesive material may be deposited on the absorbentparticulate polymer material and the substrate to cover the absorbentparticulate polymer material on the substrate and form an absorbentlayer.

According to another aspect of this invention, an apparatus for making adisposable absorbent article may comprise an absorbent particulatepolymer material feeder, a support comprising a grid, a printing roll,and a thermoplastic adhesive material applicator. The support maycomprise a grid including a plurality of cross bars extendingsubstantially parallel to and spaced from one another so as to formchannels extending between the plurality of cross bars. The printingroll may be structured for receiving absorbent particulate polymermaterial from the absorbent particulate polymer material feeder and havea peripheral surface and a plurality of reservoirs in the peripheralsurface arranged in an array comprising rows extending substantiallyparallel to and spaced from one another. The support and printing rollmay be arranged such that the plurality of cross bars are substantiallyparallel to the rows of the plurality of reservoirs in the peripheralsurface, so that, when the printing roll rotates, the plurality ofreservoirs roll receive absorbent particulate polymer material from theabsorbent particulate polymer material feeder and deposit the absorbentparticulate polymer material on the substrate in a pattern such that theabsorbent particulate polymer material collects in rows on the substrateformed between the plurality of cross bars. The thermoplastic adhesivematerial applicator may apply thermoplastic adhesive material applicatoron the absorbent particulate polymer material and the substrate to coverthe absorbent particulate polymer material on the substrate and form anabsorbent layer.

According to yet another aspect of this invention, a disposableabsorbent article may comprise a chassis, including a topsheet and abacksheet, and a substantially cellulose free absorbent core locatedbetween the topsheet and the backsheet. The absorbent core may have alongitudinal axis, and may include first and second absorbent layers.The first absorbent layer may include a first substrate and the secondabsorbent layer including a second substrate. The first and secondabsorbent layers may further include absorbent particulate polymermaterial deposited on the first and second substrates and thermoplasticadhesive material may cover the absorbent particulate polymer materialon the respective first and second substrates. The absorbent particulatepolymer material may be deposited on the first and second substrates inrespective patterns and each pattern may comprise rows of the absorbentparticulate polymer material spaced from one another extendingsubstantially perpendicular to the longitudinal axis and junction areasextending in between the rows and substantially perpendicular to thelongitudinal axis. The first and second absorbent layers may be combinedtogether such that at least a portion of said thermoplastic adhesivematerial of the first absorbent layer contacts at least a portion of thethermoplastic adhesive material of the second absorbent layer, theabsorbent particulate polymer material may be disposed between the firstand second substrates in an absorbent particulate polymer material area,the absorbent particulate polymer material may be substantiallycontinuously distributed across the absorbent particulate polymermaterial area, and the respective patterns may be offset from oneanother so that the rows of both patterns are substantially parallel toone another and the rows of each pattern fit between the rows of theother of the patterns. Other features and advantages of the inventionmay be apparent from reading the following detailed description,drawings, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a diaper in accordance with an embodiment ofthe present invention.

FIG. 2 is a cross sectional view of the diaper shown in FIG. 1 takenalong the sectional line 2-2 of FIG. 1.

FIG. 3 is a partial longitudinal cross sectional view of an absorbentcore layer in accordance with an embodiment of this invention.

FIG. 4 is a partial longitudinal cross sectional view of an absorbentcore layer in accordance with another embodiment of this invention.

FIG. 5 is a plan view of the absorbent core layer illustrated in FIG. 3.

FIG. 6 is a plan view of a second absorbent core layer in accordancewith an embodiment of this invention.

FIG. 7 is a partial longitudinal sectional view of an absorbent corecomprising a combination of the first and second absorbent core layersillustrated in FIGS. 5 and 6.

FIG. 8 is a plan view of the absorbent core illustrated in FIG. 7.

FIG. 9 is a schematic representation of a rheometer.

FIG. 10 is a schematic illustration of a process for making an absorbentcore in accordance with an embodiment of this invention.

FIG. 11 is a partial sectional view of an apparatus for making anabsorbent core in accordance with an embodiment of this invention.

FIG. 12 is a perspective view of a supporting roll illustrated in FIG.11.

FIG. 13 is a partial perspective view of a grid which forms part of thesupporting roll illustrated in FIG. 12.

FIG. 14 is a perspective view of a printing roll illustrated in FIG. 11.

FIG. 15 is a partial perspective view of the printing roll illustratedin FIG. 14 showing absorbent particulate polymer material reservoirs.

FIG. 16 is a partial perspective view of an alternative printing rollshowing absorbent particulate polymer material reservoirs.

FIG. 17 is a partial perspective view of an alternative printing rollshowing absorbent particulate polymer material reservoirs.

DETAILED DESCRIPTION OF THE INVENTION

As summarized above, this invention encompasses a method and apparatusfor making a disposable absorbent article comprising absorbentparticulate polymer material deposited on a substrate and a resultingdisposable absorbent article. Embodiments of such method and apparatusand resulting disposable absorbent articles are described hereinbelowafter the following definitions.

Definitions

“Absorbent article” refers to devices that absorb and contain bodyexudates, and, more specifically, refers to devices that are placedagainst or in proximity to the body of the wearer to absorb and containthe various exudates discharged from the body. Absorbent articles mayinclude diapers, training pants, adult incontinence undergarments,feminine hygiene products, breast pads, care mats, bibs, wound dressingproducts, and the like. Absorbent articles may further include floorcleaning articles, food industry articles, and the like. As used herein,the term “body fluids” or “body exudates” includes, but is not limitedto, urine, blood, vaginal discharges, breast milk, sweat and fecalmatter.

“Absorbent core” means a structure typically disposed between a topsheetand backsheet of an absorbent article for absorbing and containingliquid received by the absorbent article and may comprise one or moresubstrates, absorbent polymer material disposed on the one or moresubstrates, and a thermoplastic composition on the absorbent particulatepolymer material and at least a portion of the one or more substratesfor immobilizing the absorbent particulate polymer material on the oneor more substrates. In a multilayer absorbent core, the absorbent coremay also include a cover layer. The one or more substrates and the coverlayer may comprise a nonwoven. Further, the absorbent core issubstantially cellulose free. The absorbent core does not include anacquisition system, a topsheet, or a backsheet of the absorbent article.In a certain embodiment, the absorbent core would consist essentially ofthe one or more substrates, the absorbent polymer material, thethermoplastic composition, and optionally the cover layer.

“Absorbent polymer material,” “absorbent gelling material,” “AGM,”“superabsorbent,” and “superabsorbent material” are used hereininterchangeably and refer to cross linked polymeric materials that canabsorb at least 5 times their weight of an aqueous 0.9% saline solutionas measured using the Centrifuge Retention Capacity test (Edana441.2-01).

“Absorbent particulate polymer material” is used herein to refer to anabsorbent polymer material which is in particulate form so as to beflowable in the dry state.

“Absorbent particulate polymer material area” as used herein refers tothe area of the core wherein the first substrate 64 and second substrate72 are separated by a multiplicity of superabsorbent particles. In FIG.8, the boundary of the absorbent particulate polymer material area isdefined by the perimeter of the overlapping circles. There may be someextraneous superabsorbent particles outside of this perimeter betweenthe first substrate 64 and second substrate 72.

“Airfelt” is used herein to refer to comminuted wood pulp, which is aform of cellulosic fiber.

“Comprise,” “comprising,” and “comprises” are open ended terms, eachspecifies the presence of what follows, e.g., a component, but does notpreclude the presence of other features, e.g., elements, steps,components known in the art, or disclosed herein.

“Consisting essentially of” is used herein to limit the scope of subjectmatter, such as that in a claim, to the specified materials or steps andthose that do not materially affect the basic and novel characteristicsof the subject matter.

“Disposable” is used in its ordinary sense to mean an article that isdisposed or discarded after a limited number of usage events overvarying lengths of time, for example, less than about 20 events, lessthan about 10 events, less than about 5 events, or less than about 2events.

“Diaper” refers to an absorbent article generally worn by infants andincontinent persons about the lower torso so as to encircle the waistand legs of the wearer and that is specifically adapted to receive andcontain urinary and fecal waste. As used herein, term “diaper” alsoincludes “pants” which is defined below.

“Fiber” and “filament” are used interchangeably.

A “nonwoven” is a manufactured sheet, web or batt of directionally orrandomly orientated fibers, bonded by friction, and/or cohesion and/oradhesion, excluding paper and products which are woven, knitted, tufted,stitch-bonded incorporating binding yarns or filaments, or felted bywet-milling, whether or not additionally needled. The fibers may be ofnatural or man-made origin and may be staple or continuous filaments orbe formed in situ. Commercially available fibers have diameters rangingfrom less than about 0.001 mm to more than about 0.2 mm and they come inseveral different forms: short fibers (known as staple, or chopped),continuous single fibers (filaments or monofilaments), untwisted bundlesof continuous filaments (tow), and twisted bundles of continuousfilaments (yarn). Nonwoven fabrics can be formed by many processes suchas meltblowing, spunbonding, solvent spinning, electrospinning, andcarding. The basis weight of nonwoven fabrics is usually expressed ingrams per square meter (gsm).

“Pant” or “training pant”, as used herein, refer to disposable garmentshaving a waist opening and leg openings designed for infant or adultwearers. A pant may be placed in position on the wearer by inserting thewearer's legs into the leg openings and sliding the pant into positionabout a wearer's lower torso. A pant may be preformed by any suitabletechnique including, but not limited to, joining together portions ofthe article using refastenable and/or non-refastenable bonds (e.g.,seam, weld, adhesive, cohesive bond, fastener, etc.). A pant may bepreformed anywhere along the circumference of the article (e.g., sidefastened, front waist fastened). While the terms “pant” or “pants” areused herein, pants are also commonly referred to as “closed diapers,”“prefastened diapers,” “pull-on diapers,” “training pants,” and“diaper-pants”. Suitable pants are disclosed in U.S. Pat. No. 5,246,433,issued to Hasse, et al. on Sep. 21, 1993; U.S. Pat. No. 5,569,234,issued to Buell et al. on Oct. 29, 1996; U.S. Pat. No. 6,120,487, issuedto Ashton on Sep. 19, 2000; U.S. Pat. No. 6,120,489, issued to Johnsonet al. on Sep. 19, 2000; U.S. Pat. No. 4,940,464, issued to Van Gompelet al. on Jul. 10, 1990; U.S. Pat. No. 5,092,861, issued to Nomura etal. on Mar. 3, 1992; U.S. Patent Publication No. 2003/0233082 A1,entitled “Highly Flexible And Low Deformation Fastening Device”, filedon Jun. 13, 2002; U.S. Pat. No. 5,897,545, issued to Kline et al. onApr. 27, 1999; U.S. Pat. No. 5,957,908, issued to Kline et al on Sep.28, 1999.

“Substantially cellulose free” is used herein to describe an article,such as an absorbent core, that contains less than 10% by weightcellulosic fibers, less than 5% cellulosic fibers, less than 1%cellulosic fibers, no cellulosic fibers, or no more than an immaterialamount of cellulosic fibers. An immaterial amount of cellulosic materialwould not materially affect the thinness, flexibility, or absorbency ofan absorbent core.

“Substantially continuously distributed” as used herein indicates thatwithin the absorbent particulate polymer material area, the firstsubstrate 64 and second substrate 72 are separated by a multiplicity ofsuperabsorbent particles. It is recognized that there may be minorincidental contact areas between the first substrate 64 and secondsubstrate 72 within the absorbent particulate polymer material area.Incidental contact areas between the first substrate 64 and secondsubstrate 72 may be intentional or unintentional (e.g. manufacturingartifacts) but do not form geometries such as pillows, pockets, tubes,quilted patterns and the like.

“Thermoplastic adhesive material” as used herein is understood tocomprise a polymer composition from which fibers are formed and appliedto the superabsorbent material with the intent to immobilize thesuperabsorbent material in both the dry and wet state. The thermoplasticadhesive material of the present invention forms a fibrous network overthe superabsorbent material.

“Thickness” and “caliper” are used herein interchangeably.

Absorbent Articles

FIG. 1 is a plan view of a diaper 10 according to a certain embodimentof the present invention. The diaper 10 is shown in its flat out,uncontracted state (i.e., without elastic induced contraction) andportions of the diaper 10 are cut away to more clearly show theunderlying structure of the diaper 10. A portion of the diaper 10 thatcontacts a wearer is facing the viewer in FIG. 1. The diaper 10generally may comprise a chassis 12 and an absorbent core 14 disposed inthe chassis.

The chassis 12 of the diaper 10 in FIG. 1 may comprise the main body ofthe diaper 10. The chassis 12 may comprise an outer covering 16including a topsheet 18, which may be liquid pervious, and/or abacksheet 20, which may be liquid impervious. The absorbent core 14 maybe encased between the topsheet 18 and the backsheet 20. The chassis 12may also include side panels 22, elasticized leg cuffs 24, and anelastic waist feature 26.

The leg cuffs 24 and the elastic waist feature 26 may each typicallycomprise elastic members 28. One end portion of the diaper 10 may beconfigured as a first waist region 30 of the diaper 10. An opposite endportion of the diaper 10 may be configured as a second waist region 32of the diaper 10. An intermediate portion of the diaper 10 may beconfigured as a crotch region 34, which extends longitudinally betweenthe first and second waist regions 30 and 32. The waist regions 30 and32 may include elastic elements such that they gather about the waist ofthe wearer to provide improved fit and containment (elastic waistfeature 26). The crotch region 34 is that portion of the diaper 10which, when the diaper 10 is worn, is generally positioned between thewearer's legs.

The diaper 10 is depicted in FIG. 1 with its longitudinal axis 36 andits transverse axis 38. The periphery 40 of the diaper 10 is defined bythe outer edges of the diaper 10 in which the longitudinal edges 42 rungenerally parallel to the longitudinal axis 36 of the diaper 10 and theend edges 44 run between the longitudinal edges 42 generally parallel tothe transverse axis 38 of the diaper 10. The chassis 12 may alsocomprise a fastening system, which may include at least one fasteningmember 46 and at least one stored landing zone 48.

The diaper 20 may also include such other features as are known in theart including front and rear ear panels, waist cap features, elasticsand the like to provide better fit, containment and aestheticcharacteristics. Such additional features are well known in the art andare e.g., described in U.S. Pat. No. 3,860,003 and U.S. Pat. No.5,151,092.

In order to keep the diaper 10 in place about the wearer, at least aportion of the first waist region 30 may be attached by the fasteningmember 46 to at least a portion of the second waist region 32 to formleg opening(s) and an article waist. When fastened, the fastening systemcarries a tensile load around the article waist. The fastening systemmay allow an article user to hold one element of the fastening system,such as the fastening member 46, and connect the first waist region 30to the second waist region 32 in at least two places. This may beachieved through manipulation of bond strengths between the fasteningdevice elements.

According to certain embodiments, the diaper 10 may be provided with are-closable fastening system or may alternatively be provided in theform of a pant-type diaper. When the absorbent article is a diaper, itmay comprise a re-closable fastening system joined to the chassis forsecuring the diaper to a wearer. When the absorbent article is apant-type diaper, the article may comprise at least two side panelsjoined to the chassis and to each other to form a pant. The fasteningsystem and any component thereof may include any material suitable forsuch a use, including but not limited to plastics, films, foams,nonwoven, woven, paper, laminates, fiber reinforced plastics and thelike, or combinations thereof In certain embodiments, the materialsmaking up the fastening device may be flexible. The flexibility mayallow the fastening system to conform to the shape of the body and thus,reduce the likelihood that the fastening system will irritate or injurethe wearer's skin.

For unitary absorbent articles, the chassis 12 and absorbent core 14 mayform the main structure of the diaper 10 with other features added toform the composite diaper structure. While the topsheet 18, thebacksheet 20, and the absorbent core 14 may be assembled in a variety ofwell-known configurations, preferred diaper configurations are describedgenerally in U.S. Pat. No. 5,554,145 entitled “Absorbent Article WithMultiple Zone Structural Elastic-Like Film Web Extensible Waist Feature”issued to Roe et al. on Sep. 10, 1996; U.S. Pat. No. 5,569,234 entitled“Disposable Pull-On Pant” issued to Buell et al. on Oct. 29, 1996; andU.S. Pat. No. 6,004,306 entitled “Absorbent Article WithMulti-Directional Extensible Side Panels” issued to Robles et al. onDec. 21, 1999.

The topsheet 18 in FIG. 1 may be fully or partially elasticized or maybe foreshortened to provide a void space between the topsheet 18 and theabsorbent core 14. Exemplary structures including elasticized orforeshortened topsheets are described in more detail in U.S. Pat. No.5,037,416 entitled “Disposable Absorbent Article Having ElasticallyExtensible Topsheet” issued to Allen et al. on Aug. 6, 1991; and U.S.Pat. No. 5,269,775 entitled “Trisection Topsheets for DisposableAbsorbent Articles and Disposable Absorbent Articles Having SuchTrisection Topsheets” issued to Freeland et al. on Dec. 14, 1993.

The backsheet 20 may be joined with the topsheet 18. The backsheet 20may prevent the exudates absorbed by the absorbent core 14 and containedwithin the diaper 10 from soiling other external articles that maycontact the diaper 10, such as bed sheets and undergarments. In certainembodiments, the backsheet 20 may be substantially impervious to liquids(e.g., urine) and comprise a laminate of a nonwoven and a thin plasticfilm such as a thermoplastic film having a thickness of about 0.012 mm(0.5 mil) to about 0.051 mm (2.0 mils). Suitable backsheet films includethose manufactured by Tredegar Industries Inc. of Terre Haute, Ind. andsold under the trade names X15306, X10962, and X10964. Other suitablebacksheet materials may include breathable materials that permit vaporsto escape from the diaper 10 while still preventing liquid exudates frompassing through the backsheet 10. Exemplary breathable materials mayinclude materials such as woven webs, nonwoven webs, composite materialssuch as film-coated nonwoven webs, and microporous films such asmanufactured by Mitsui Toatsu Co., of Japan under the designation ESPOIRNO and by EXXON Chemical Co., of Bay City, Tex., under the designationEXXAIRE. Suitable breathable composite materials comprising polymerblends are available from Clopay Corporation, Cincinnati, Ohio under thename HYTREL blend P18-3097. Such breathable composite materials aredescribed in greater detail in PCT Application No. WO 95/16746,published on Jun. 22, 1995 in the name of E. I. DuPont. Other breathablebacksheets including nonwoven webs and apertured formed films aredescribed in U.S. Pat. No. 5,571,096 issued to Dobrin et al. on Nov. 5,1996.

In certain embodiments, the backsheet of the present invention may havea water vapor transmission rate (WVTR) of greater than about 2000 g/24h/m², greater than about 3000 g/24 h/m², greater than about 5000 g/24h/m², greater than about 6000 g/24 h/m², greater than about 7000 g/24h/m², greater than about 8000 g/24 h/m², greater than about 9000 g/24h/m², greater than about 10000 g/24 h/m², greater than about 11000 g/24h/m², greater than about 12000 g/24 h/m², greater than about 15000 g/24h/m², measured according to WSP 70.5 (08) at 37.8° C. and 60% RelativeHumidity.

FIG. 2 shows a cross section of FIG. 1 taken along the sectional line2-2 of FIG. 1. Starting from the wearer facing side, the diaper 10 maycomprise the topsheet 18, the components of the absorbent core 14, andthe backsheet 20. According to a certain embodiment, diaper 10 may alsocomprise an acquisition system 50 disposed between the liquid permeabletopsheet 18 and a wearer facing side of the absorbent core 14. Theacquisition system 50 may be in direct contact with the absorbent core.The acquisition system 50 may comprise a single layer or multiplelayers, such as an upper acquisition layer 52 facing towards thewearer's skin and a lower acquisition 54 layer facing the garment of thewearer. According to a certain embodiment, the acquisition system 50 mayfunction to receive a surge of liquid, such as a gush of urine. In otherwords, the acquisition system 50 may serve as a temporary reservoir forliquid until the absorbent core 14 can absorb the liquid.

In a certain embodiment, the acquisition system 50 may comprisechemically cross-linked cellulosic fibers. Such cross-linked cellulosicfibers may have desirable absorbency properties. Exemplary chemicallycross-linked cellulosic fibers are disclosed in U.S. Pat. No. 5,137,537.In certain embodiments, the chemically cross-linked cellulosic fibersare cross-linked with between about 0.5 mole % and about 10.0 mole % ofa C₂ to C₉ polycarboxylic cross-linking agent or between about 1.5 mole% and about 6.0 mole % of a C₂ to C₉ polycarboxylic cross-linking agentbased on glucose unit. Citric acid is an exemplary cross-linking agent.In other embodiments, polyacrylic acids may be used. Further, accordingto certain embodiments, the cross-linked cellulosic fibers have a waterretention value of about 25 to about 60, or about 28 to about 50, orabout 30 to about 45. A method for determining water retention value isdisclosed in U.S. Pat. No. 5,137,537. According to certain embodiments,the cross-linked cellulosic fibers may be crimped, twisted, or curled,or a combination thereof including crimped, twisted, and curled.

In a certain embodiment, one or both of the upper and lower acquisitionlayers 52 and 54 may comprise a non-woven, which may be hydrophilic.Further, according to a certain embodiment, one or both of the upper andlower acquisition layers 52 and 54 may comprise the chemicallycross-linked cellulosic fibers, which may or may not form part of anonwoven material. According to an exemplary embodiment, the upperacquisition layer 52 may comprise a nonwoven, without the cross-linkedcellulosic fibers, and the lower acquisition layer 54 may comprise thechemically cross-linked cellulosic fibers. Further, according to anembodiment, the lower acquisition layer 54 may comprise the chemicallycross-linked cellulosic fibers mixed with other fibers such as naturalor synthetic polymeric fibers. According to exemplary embodiments, suchother natural or synthetic polymeric fibers may include high surfacearea fibers, thermoplastic binding fibers, polyethylene fibers,polypropylene fibers, PET fibers, rayon fibers, lyocell fibers, andmixtures thereof. According to a particular embodiment, the loweracquisition layer 54 has a total dry weight, the cross-linked cellulosicfibers are present on a dry weight basis in the upper acquisition layerin an amount from about 30% to about 95% by weight of the loweracquisition layer 54, and the other natural or synthetic polymericfibers are present on a dry weight basis in the lower acquisition layer54 in an amount from about 70% to about 5% by weight of the loweracquisition layer 54. According to another embodiment, the cross-linkedcellulosic fibers are present on a dry weight basis in the firstacquisition layer in an amount from about 80% to about 90% by weight ofthe lower acquisition layer 54, and the other natural or syntheticpolymeric fibers are present on a dry weight basis in the loweracquisition layer 54 in an amount from about 20% to about 10% by weightof the lower acquisition layer 54.

According to a certain embodiment, the lower acquisition layer 54desirably has a high fluid uptake capability. Fluid uptake is measuredin grams of absorbed fluid per gram of absorbent material and isexpressed by the value of “maximum uptake.” A high fluid uptakecorresponds therefore to a high capacity of the material and isbeneficial, because it ensures the complete acquisition of fluids to beabsorbed by an acquisition material. According to exemplary embodiments,the lower acquisition layer 54 has a maximum uptake of about 10 g/g.

A relevant attribute of the upper acquisition layer 54 is its MedianDesorption Pressure, MDP. The MDP is a measure of the capillary pressurethat is required to dewater the lower acquisition layer 54 to about 50%of its capacity at 0 cm capillary suction height under an appliedmechanical pressure of 0.3 psi. Generally, a relatively lower MDP may beuseful. The lower MDP may allow the lower acquisition layer 54 to moreefficiently drain the upper acquisition material. Without wishing to bebound by theory, a given distribution material may have a definablecapillary suction. The ability of the lower acquisition layer 54 to moveliquid vertically via capillary forces will be directly impacted bygravity and the opposing capillary forces associated with desorption ofthe upper acquisition layer. Minimizing these capillary forces maypositively impact the performance of the lower acquisition layer 54.However, in a certain embodiment the lower acquisition layer 54 may alsohave adequate capillary absorption suction in order to drain the layersabove (upper acquisition layer 52 and topsheet 18, in particular) and totemporarily hold liquid until the liquid can be partitioned away by theabsorbent core components. Therefore, in a certain embodiment, the loweracquisition layer 54 may have a minimum MDP of greater than 5 cm.Further, according to exemplary embodiments, the lower acquisition layer54 has an MDP value of less than about 20.5 cm H₂O, or less than about19 cm H₂O, or less than about 18 cm H₂O to provide for fast acquisition.

The methods for determining MDP and maximum uptake are disclosed in U.S.Patent Application Publication No. 2007/0118087 A1. For example,according to a first embodiment, the lower acquisition layer 54 maycomprise about 70% by weight of chemically cross-linked cellulosefibers, about 10% by weight polyester (PET), and about 20% by weightuntreated pulp fibers. According to a second embodiment, the loweracquisition layer 54 may comprise about 70% by weight chemicallycross-linked cellulose fibers, about 20% by weight lyocell fibers, andabout 10% by weight PET fibers. According to a third embodiment, thelower acquisition layer 54 may comprise about 68% by weight chemicallycross-linked cellulose fibers, about 16% by weight untreated pulpfibers, and about 16% by weight PET fibers. In one embodiment, the loweracquisition layer 54 may comprise from about 90-100% by weightchemically cross-linked cellulose fibers.

Suitable non-woven materials for the upper and lower acquisition layers52 and 54 include, but are not limited to SMS material, comprising aspunbonded, a melt-blown and a further spunbonded layer. In certainembodiments, permanently hydrophilic non-wovens, and in particular,nonwovens with durably hydrophilic coatings are desirable. Anothersuitable embodiment comprises a SMMS-structure. In certain embodiments,the non-wovens are porous.

In certain embodiments, suitable non-woven materials may include, butare not limited to synthetic fibers, such as PE, PET, and PP. Aspolymers used for nonwoven production may be inherently hydrophobic,they may be coated with hydrophilic coatings. One way to producenonwovens with durably hydrophilic coatings, is via applying ahydrophilic monomer and a radical polymerization initiator onto thenonwoven, and conducting a polymerization activated via UV lightresulting in monomer chemically bound to the surface of the nonwoven asdescribed in co-pending U.S. Patent Publication No. 2005/0159720.Another way to produce nonwovens with durably hydrophilic coatings is tocoat the nonwoven with hydrophilic nanoparticles as described inco-pending applications U.S. Pat. No. 7,112,621 to Rohrbaugh et al. andin PCT Application Publication WO 02/064877.

Typically, nanoparticles have a largest dimension of below 750 nm.Nanoparticles with sizes ranging from 2 to 750 nm may be economicallyproduced. An advantage of nanoparticles is that many of them can beeasily dispersed in water solution to enable coating application ontothe nonwoven, they typically form transparent coatings, and the coatingsapplied from water solutions are typically sufficiently durable toexposure to water. Nanoparticles can be organic or inorganic, syntheticor natural. Inorganic nanoparticles generally exist as oxides,silicates, and/or, carbonates. Typical examples of suitablenanoparticles are layered clay minerals (e.g., LAPONITE™ from SouthernClay Products, Inc. (USA), and Boehmite alumina (e.g., Disperal P2™ fromNorth American Sasol. Inc.). According to a certain embodiment, asuitable nanoparticle coated non-woven is that disclosed in U.S. PatentApplication Publication No. 2004/0158212 entitled “Disposable absorbentarticle comprising a durable hydrophilic core wrap” to EkaterinaAnatolyevna Ponomarenko and Mattias NMN Schmidt.

Further useful non-wovens are described in U.S. Pat. No. 6,645,569 toCramer et al., U.S. Pat. No. 6,863,933 to Cramer et al., U.S. Pat. No.7,112,621 to Rohrbaugh et al., and U.S. Patent Application PublicationNumbers. 2003/0148684 A1 to Cramer et al. and 2005/0008839 A1 to Crameret al.

In some cases, the nonwoven surface can be pre-treated with high energytreatment (corona, plasma) prior to application of nanoparticlecoatings. High energy pre-treatment typically temporarily increases thesurface energy of a low surface energy surface (such as PP) and thusenables better wetting of a nonwoven by the nanoparticle dispersion inwater.

Notably, permanently hydrophilic non-wovens are also useful in otherparts of an absorbent article. For example, topsheets and absorbent corelayers comprising permanently hydrophilic non-wovens as described abovehave been found to work well.

According to a certain embodiment, the upper acquisition layer 52 maycomprise a material that provides good recovery when external pressureis applied and removed. Further, according to a certain embodiment, theupper acquisition layer 52 may comprise a blend of different fibersselected, for example from the types of polymeric fibers describedabove. In some embodiments, at least a portion of the fibers may exhibita spiral-crimp which has a helical shape. In some embodiments, the upperacquisition layer 52 may comprise fibers having different degrees ortypes of crimping, or both. For example, one embodiment may include amixture of fibers having about 8 to about 12 crimps per inch (cpi) orabout 9 to about 10 cpi, and other fibers having about 4 to about 8 cpior about 5 to about 7 cpi. Different types of crimps include, but arenot limited to a 2D crimp or “flat crimp” and a 3D or spiral-crimp.According to a certain embodiment, the fibers may include bi-componentfibers, which are individual fibers each comprising different materials,usually a first and a second polymeric material. It is believed that theuse of side-by-side bi-component fibers is beneficial for imparting aspiral-crimp to the fibers.

The upper acquisition layer 52 may be stabilized by a latex binder, forexample a styrene-butadiene latex binder (SB latex), in a certainembodiment. Processes for obtaining such lattices are known, forexample, from EP 149 880 (Kwok) and US 2003/0105190 (Diehl et al.). Incertain embodiments, the binder may be present in the upper acquisitionlayer 52 in excess of about 12%, about 14% or about 16% by weight. Forcertain embodiments, SB latex is available under the trade name GENFLO™3160 (OMNOVA Solutions Inc.; Akron, Ohio).

The absorbent core 14 in FIGS. 1-8 generally is disposed between thetopsheet 18 and the backsheet 20 and comprises two layers, a firstabsorbent layer 60 and a second absorbent layer 62. As best shown inFIG. 3, the first absorbent layer 60 of the absorbent core 14 comprisesa substrate 64, an absorbent particular polymer material 66 on thesubstrate 64, and a thermoplastic composition 68 on the absorbentparticulate polymer material 66 and at least portions of the firstsubstrate 64 as an adhesive for covering and immobilizing the absorbentparticulate polymer material 66 on the first substrate 64. According toanother embodiment illustrated in FIG. 4, the first absorbent layer 60of the absorbent core 14 may also include a cover layer 70 on thethermoplastic composition 68.

Likewise, as best illustrated in FIG. 7, the second absorbent layer 62of the absorbent core 14 may also include a substrate 72, an absorbentparticulate polymer material 74 on the second substrate 72, and athermoplastic composition 76 on the absorbent particulate polymermaterial 74 and at least a portion of the second substrate 72 forimmobilizing the absorbent particulate polymer material 74 on the secondsubstrate 72. Although not illustrated, the second absorbent layer 62may also include a cover layer such as the cover layer 70 illustrated inFIG. 4.

The substrate 64 of the first absorbent layer 60 may be referred to as adusting layer and has a first surface 78 which faces the backsheet 20 ofthe diaper 10 and a second surface 80 which faces the absorbentparticulate polymer material 66. Likewise, the substrate 72 of thesecond absorbent layer 62 may be referred to as a core cover and has afirst surface 82 facing the topsheet 18 of the diaper 10 and a secondsurface 84 facing the absorbent particulate polymer material 74. Thefirst and second substrates 64 and 72 may be adhered to one another withadhesive about the periphery to form an envelope about the absorbentparticulate polymer materials 66 and 74 to hold the absorbentparticulate polymer material 66 and 74 within the absorbent core 14.

According to a certain embodiment, the substrates 64 and 72 of the firstand second absorbent layers 60 and 62 may be a non-woven material, suchas those nonwoven materials described above. In certain embodiments, thenon-wovens are porous and in one embodiment has a pore size of about 32microns.

As illustrated in FIGS. 1-8, the absorbent particulate polymer material66 and 74 is deposited on the respective substrates 64 and 72 of thefirst and second absorbent layers 60 and 62 in clusters 90 of particlesto form a grid pattern 92 comprising rows 94 of the absorbentparticulate polymer material 66 and 74 spaced from one another andjunction areas 96 between the rows 94. The thermoplastic adhesivematerial 68 and 76 may not contact the nonwoven substrate or theauxiliary adhesive directly in the rows 94 except perhaps in areas wherethere is lesser absorbent particulate polymer material 66 and 74;junction areas 96 are areas where the thermoplastic adhesive materialdoes contact the nonwoven substrate or the auxiliary adhesive directly.The junction areas 96 in the grid pattern 92 contain little or noabsorbent particulate polymer material 66 and 74. The rows 94 andjunction areas 96 are elongate and extend in a cross direction which issubstantially perpendicular to the longitudinal axis 100 of theabsorbent core 14.

The grid pattern shown in FIGS. 5, 6, and 8 is a rectangular grid withregular spacing and size of the rows. Other grid patterns includinghexagonal, rhombic, orthorhombic, parallelogram, triangular, square, andcombinations thereof may also be used. According to a certainembodiment, the spacing between the rows 94 may be regular.

The size of the rows 94 in the grid patterns 92 may vary. According tocertain embodiments, the width 119 of the rows 94 in the grid patterns92 ranges from about 8 mm to about 12 mm. In a certain embodiment, thewidth of the rows 94 is about 10 mm. The junction areas 96, on the otherhand, in certain embodiments, have a width or larger span of less thanabout 3 mm to about 3 mm. According to a certain embodiment, theabsorbent particulate polymer 66 and 74 form substantially continuousrows, but the clusters 90 of absorbent particulate polymer 66 and 74 mayform rows of intermittent absorbent particulate polymer 66 and 74according to other embodiments.

As shown in FIGS. 5, 6 and 8, the absorbent core 14 has a longitudinalaxis 100 extending from a rear end 102 to a front end 104 and atransverse axis 106 perpendicular to the longitudinal axis 100 extendingfrom a first edge 108 to a second edge 110. The grid pattern 92 ofabsorbent particulate polymer material clusters 90 is arranged on thesubstrates 64 and 72 of the respective absorbent layers 60 and 62 suchthat the rows 94 and junction areas 96 are substantially perpendicularto the longitudinal axis 100 of the absorbent core 14. Accordingly,certain embodiments of the absorbent core 14 may be made so thatboundaries of the grid patterns 92 of the absorbent layers 60 and 62 aresubstantially straight.

As best seen in FIGS. 7 and 8, the first and second layers 60 and 62 maybe combined to form the absorbent core 14. The absorbent core 14 has anabsorbent particulate polymer material area 114 bounded by a patternlength 116 and a pattern width 118. The extent and shape of theabsorbent particulate polymer material area 114 may vary depending onthe desired application of the absorbent core 14 and the particularabsorbent article in which it may be incorporated. In a certainembodiment, however, the absorbent particulate polymer material area 114extends substantially entirely across the absorbent core 14, such as isillustrated in FIG. 8.

The first and second absorbent layers 60 and 62 may be combined togetherto form the absorbent core 14 such that the grid patterns 92 of therespective first and second absorbent layers 62 and 64 are offset fromone another along the length of the absorbent core 14. The length of theabsorbent core 14 extends along the longitudinal axis 100 of theabsorbent core 14 and is parallel thereto. The respective grid patterns92 may be offset in the direction of the longitudinal axis 100 (themachine direction) such that the absorbent particulate polymer material66 and 74 is substantially continuously distributed across the absorbentparticulate polymer area 114. In a certain embodiment, absorbentparticulate polymer material 66 and 74 is substantially continuouslydistributed across the absorbent particulate polymer material area 114despite the individual grid patterns 92 comprising absorbent particulatepolymer material 66 and 74 discontinuously distributed across the firstand second substrates 64 and 72 due to the alternating rows 94 andjunction areas 96. In a certain embodiment, the grid patterns may beoffset such that the rows 94 of the first absorbent layer 60 face thejunction areas 96 of the second absorbent layer 62 and the rows 94 ofthe second absorbent layer 62 face the junction areas 96 of the firstabsorbent layer 60. In other words, the rows 94 and junction areas 96 ofthe first absorbent layer 60 are substantially parallel to the rows 94and junction areas 96 of the second absorbent layer 62 and the rows 94of the first absorbent layer 60 are disposed at least partially betweenthe rows 94 of the second absorbent layer 62. When the rows 94 andjunction areas 96 are appropriately sized and arranged, the resultingcombination of absorbent particulate polymer material 66 and 74 is asubstantially continuous layer of absorbent particular polymer materialacross the absorbent particulate polymer material area 114 of theabsorbent core 14. In a certain embodiment, respective grid patterns 92of the first and second absorbent layer 60 and 62 may be substantiallythe same and the respective patterns are offset one half cycle relativeto one another in the machine direction.

In the latter case, the respective patterns 92 of absorbent particulatepolymer 66 and 74 may also be offset in a direction substantiallyperpendicular to the longitudinal axis 100 (the cross direction) so thatthe resulting combination of absorbent particulate polymer material 66and 74 is a substantially continuous layer of absorbent particularpolymer material across the absorbent particulate polymer material area114 of the absorbent core 14.

In a certain embodiment as illustrated in FIG. 8, the amount ofabsorbent particulate polymer material 66 and 74 may vary along thelength 116 of the grid pattern 92. In a certain embodiment, the gridpattern may be divided into absorbent zones 120, 122, 124, and 126, inwhich the amount of absorbent particulate polymer material 66 and 74varies from zone to zone. As used herein, “absorbent zone” refers to aregion of the absorbent particulate polymer material area havingboundaries that are perpendicular to the longitudinal axis shown in FIG.8. The amount of absorbent particulate polymer material 66 and 74 may,in a certain embodiment, gradually transition from one of the pluralityof absorbent zones 120, 122, 124, and 126 to another. This gradualtransition in amount of absorbent particulate polymer material 66 and 74may reduce the possibility of cracks forming in the absorbent core 14.

The amount of absorbent particulate polymer material 66 and 74 presentin the absorbent core 14 may vary, but in certain embodiments, ispresent in the absorbent core in an amount greater than about 80% byweight of the absorbent core, or greater than about 85% by weight of theabsorbent core, or greater than about 90% by weight of the absorbentcore, or greater than about 95% by weight of the core. In a particularembodiment, the absorbent core 14 consists essentially of the first andsecond substrates 64 and 72, the absorbent particulate polymer material66 and 74, and the thermoplastic adhesive composition 68 and 76. In anembodiment, the absorbent core 14 may be substantially cellulose free.

According to certain embodiments, the weight of absorbent particulatepolymer material 66 and 74 in at least one freely selected first squaremeasuring 1 cm×1 cm may be at least about 10%, or 20%, or 30%, 40% or50% higher than the weight of absorbent particulate polymer material 66and 74 in at least one freely selected second square measuring 1 cm×1cm. In a certain embodiment, the first and the second square arecentered about the longitudinal axis.

The absorbent particulate polymer material area, according to anexemplary embodiment, may have a relatively narrow width in the crotcharea of the absorbent article for increased wearing comfort. Hence, theabsorbent particulate polymer material area, according to an embodiment,may have a width as measured along a transverse line which is positionedat equal distance to the front edge and the rear edge of the absorbentarticle, which is less than about 100 mm, 90 mm, 80 mm, 70 mm, 60 mm oreven less than about 50 mm.

It has been found that, for most absorbent articles such as diapers, theliquid discharge occurs predominately in the front half of the diaper.The front half of the absorbent core 14 should therefore comprise mostof the absorbent capacity of the core. Thus, according to certainembodiments, the front half of said absorbent core 14 may comprise morethan about 60% of the superabsorbent material, or more than about 65%,70%, 75%, 80%, 85%, or 90% of the superabsorbent material.

In certain embodiments, the absorbent core 14 may further comprise anyabsorbent material that is generally compressible, conformable,non-irritating to the wearer's skin, and capable of absorbing andretaining liquids such as urine and other certain body exudates. In suchembodiments, the absorbent core 14 may comprise a wide variety ofliquid-absorbent materials commonly used in disposable diapers and otherabsorbent articles such as comminuted wood pulp, which is generallyreferred to as airfelt, creped cellulose wadding, melt blown polymers,including co-form, chemically stiffened, modified or cross-linkedcellulosic fibers, tissue, including tissue wraps and tissue laminates,absorbent foams, absorbent sponges, or any other known absorbentmaterial or combinations of materials. The absorbent core 14 may furthercomprise minor amounts (typically less than about 10%) of materials,such as adhesives, waxes, oils and the like.

Exemplary absorbent structures for use as the absorbent assemblies aredescribed in U.S. Pat. No. 4,610,678 (Weisman et al.); U.S. Pat. No.4,834,735 (Alemany et al.); U.S. Pat. No. 4,888,231 (Angstadt); U.S.Pat. No. 5,260,345 (DesMarais et al.); U.S. Pat. No. 5,387,207 (Dyer etal.); U.S. Pat. No. 5,397,316 (LaVon et al.); and U.S. Pat. No.5,625,222 (DesMarais et al.).

The thermoplastic adhesive material 68 and 76 may serve to cover and atleast partially immobilize the absorbent particulate polymer material 66and 74. In one embodiment of the present invention, the thermoplasticadhesive material 68 and 76 can be disposed essentially uniformly withinthe absorbent particulate polymer material 66 and 74, between thepolymers. However, in a certain embodiment, the thermoplastic adhesivematerial 68 and 76 may be provided as a fibrous layer which is at leastpartially in contact with the absorbent particulate polymer material 66and 74 and partially in contact with the substrate layers 64 and 72 ofthe first and second absorbent layers 60 and 62. FIGS. 3, 4, and 7 showsuch a structure, and in that structure, the absorbent particulatepolymer material 66 and 74 is provided as a discontinuous layer, and alayer of fibrous thermoplastic adhesive material 68 and 76 is laid downonto the layer of absorbent particulate polymer material 66 and 74, suchthat the thermoplastic adhesive material 68 and 76 is in direct contactwith the absorbent particulate polymer material 66 and 74, but also indirect contact with the second surfaces 80 and 84 of the substrates 64and 72, where the substrates are not covered by the absorbentparticulate polymer material 66 and 74. This imparts an essentiallythree-dimensional structure to the fibrous layer of thermoplasticadhesive material 68 and 76, which in itself is essentially atwo-dimensional structure of relatively small thickness, as compared tothe dimension in length and width directions. In other words, thethermoplastic adhesive material 68 and 76 undulates between theabsorbent particulate polymer material 68 and 76 and the second surfacesof the substrates 64 and 72.

Thereby, the thermoplastic adhesive material 68 and 76 may providecavities to cover the absorbent particulate polymer material 66 and 74,and thereby immobilizes this material. In a further aspect, thethermoplastic adhesive material 68 and 76 bonds to the substrates 64 and72 and thus affixes the absorbent particulate polymer material 66 and 74to the substrates 64 and 72. Thus, in accordance with certainembodiments, the thermoplastic adhesive material 68 and 76 immobilizesthe absorbent particulate polymer material 66 and 74 when wet, such thatthe absorbent core 14 achieves an absorbent particulate polymer materialloss of no more than about 70%, 60%, 50%, 40%, 30%, 20%, 10% accordingto the Wet Immobilization Test described herein. Some thermoplasticadhesive materials will also penetrate into both the absorbentparticulate polymer material 66 and 74 and the substrates 64 and 72,thus providing for further immobilization and affixation. Of course,while the thermoplastic adhesive materials disclosed herein provide amuch improved wet immobilization (i.e., immobilization of absorbentmaterial when the article is wet or at least partially loaded), thesethermoplastic adhesive materials may also provide a very goodimmobilization of absorbent material when the absorbent core 14 is dry.The thermoplastic adhesive material 68 and 76 may also be referred to asa hot melt adhesive.

Without wishing to be bound by theory, it has been found that thosethermoplastic adhesive materials which are most useful for immobilizingthe absorbent particulate polymer material 66 and 74 combine goodcohesion and good adhesion behavior. Good adhesion may promote goodcontact between the thermoplastic adhesive material 68 and 76 and theabsorbent particulate polymer material 66 and 74 and the substrates 64and 72. Good cohesion reduces the likelihood that the adhesive breaks,in particular in response to external forces, and namely in response tostrain. When the absorbent core 14 absorbs liquid, the absorbentparticulate polymer material 66 and 74 swells and subjects thethermoplastic adhesive material 68 and 76 to external forces. In certainembodiments, the thermoplastic adhesive material 68 and 76 may allow forsuch swelling, without breaking and without imparting too manycompressive forces, which would restrain the absorbent particulatepolymer material 66 and 74 from swelling.

In accordance with certain embodiments, the thermoplastic adhesivematerial 68 and 76 may comprise, in its entirety, a single thermoplasticpolymer or a blend of thermoplastic polymers, having a softening point,as determined by the ASTM Method D-36-95 “Ring and Ball”, in the rangebetween 50° C. and 300° C., or alternatively the thermoplastic adhesivematerial may be a hot melt adhesive comprising at least onethermoplastic polymer in combination with other thermoplastic diluentssuch as tackifying resins, plasticizers and additives such asantioxidants. In certain embodiments, the thermoplastic polymer hastypically a molecular weight (Mw) of more than 10,000 and a glasstransition temperature (Tg) usually below room temperature or −6°C.<Tg<16° C. In certain embodiments, typical concentrations of thepolymer in a hot melt are in the range of about 20 to about 40% byweight. In certain embodiments, thermoplastic polymers may be waterinsensitive. Exemplary polymers are (styrenic) block copolymersincluding A-B-A triblock structures, A-B diblock structures and (A-B)nradial block copolymer structures wherein the A blocks arenon-elastomeric polymer blocks, typically comprising polystyrene, andthe B blocks are unsaturated conjugated diene or (partly) hydrogenatedversions of such. The B block is typically isoprene, butadiene,ethylene/butylene (hydrogenated butadiene), ethylene/propylene(hydrogenated isoprene), and mixtures thereof.

Other suitable thermoplastic polymers that may be employed aremetallocene polyolefins, which are ethylene polymers prepared usingsingle-site or metallocene catalysts. Therein, at least one comonomercan be polymerized with ethylene to make a copolymer, terpolymer orhigher order polymer. Also applicable are amorphous polyolefins oramorphous polyalphaolefins (APAO) which are homopolymers, copolymers orterpolymers of C2 to C8 alpha olefins.

In exemplary embodiments, the tackifying resin has typically a Mw below5,000 and a Tg usually above room temperature, typical concentrations ofthe resin in a hot melt are in the range of about 30 to about 60%, andthe plasticizer has a low Mw of typically less than 1,000 and a Tg belowroom temperature, with a typical concentration of about 0 to about 15%.

In certain embodiments, the thermoplastic adhesive material 68 and 76 ispresent in the form of fibers. In some embodiments, the fibers will havean average thickness of about 1 to about 50 micrometers or about 1 toabout 35 micrometers and an average length of about 5 mm to about 50 mmor about 5 mm to about 30 mm. To improve the adhesion of thethermoplastic adhesive material 68 and 76 to the substrates 64 and 72 orto any other layer, in particular any other non-woven layer, such layersmay be pre-treated with an auxiliary adhesive.

In certain embodiments, the thermoplastic adhesive material 68 and 76will meet at least one, or several, or all of the following parameters:

An exemplary thermoplastic adhesive material 68 and 76 may have astorage modulus G′ measured at 20° C. of at least 30,000 Pa and lessthan 300,000 Pa, or less than 200,000 Pa, or between 140,000 Pa and200,000 Pa, or less than 100,000 Pa. In a further aspect, the storagemodulus G′ measured at 35° C. may be greater than 80,000 Pa. In afurther aspect, the storage modulus G′ measured at 60° C. may be lessthan 300,000 Pa and more than 18,000 Pa, or more than 24,000 Pa, or morethan 30,000 Pa, or more than 90,000 Pa. In a further aspect, the storagemodulus G′ measured at 90° C. may be less than 200,000 Pa and more than10,000 Pa, or more than 20,000 Pa, or more then 30,000 Pa. The storagemodulus measured at 60° C. and 90° C. may be a measure for the formstability of the thermoplastic adhesive material at elevated ambienttemperatures. This value is particularly important if the absorbentproduct is used in a hot climate where the thermoplastic adhesivematerial would lose its integrity if the storage modulus G′ at 60° C.and 90° C. is not sufficiently high.

G′ is measured using a rheometer as schematically shown in FIG. 9 forthe purpose of general illustration only. The rheometer 127 is capableof applying a shear stress to the adhesive and measuring the resultingstrain (shear deformation) response at constant temperature. Theadhesive is placed between a Peltier-element acting as lower, fixedplate 128 and an upper plate 129 with a radius R of e.g., 10 mm, whichis connected to the drive shaft of a motor to generate the shear stress.The gap between both plates has a height H of e.g., 1500 micron. ThePeltier-element enables temperature control of the material (+0.5° C.).The strain rate and frequency should be chosen such that allmeasurements are made in the linear viscoelastic region.

The absorbent core 14 may also comprise an auxiliary adhesive which isnot illustrated in the figures. The auxiliary adhesive may be depositedon the first and second substrates 64 and 72 of the respective first andsecond absorbent layers 60 and 62 before application of the absorbentparticulate polymer material 66 and 74 for enhancing adhesion of theabsorbent particulate polymer materials 66 and 74 and the thermoplasticadhesive material 68 and 76 to the respective substrates 64 and 72. Theauxiliary glue may also aid in immobilizing the absorbent particulatepolymer material 66 and 74 and may comprise the same thermoplasticadhesive material as described hereinabove or may also comprise otheradhesives including but not limited to sprayable hot melt adhesives,such as H.B. Fuller Co. (St. Paul, Minn.) Product No. HL-1620-B. Theauxiliary glue may be applied to the substrates 64 and 72 by anysuitable means, but according to certain embodiments, may be applied inabout 0.5 to about 1 mm wide slots spaced about 0.5 to about 2 mm apart.

The cover layer 70 shown in FIG. 4 may comprise the same material as thesubstrates 64 and 72, or may comprise a different material. In certainembodiments, suitable materials for the cover layer 70 are the non-wovenmaterials, typically the materials described above as useful for thesubstrates 64 and 72.

Method and Apparatus for Making Absorbent Articles

A printing system 130 for making an absorbent core 14 in accordance withan embodiment of this invention is illustrated in FIG. 10 and maygenerally comprise a first printing unit 132 for forming the firstabsorbent layer 60 of the absorbent core 14 and a second printing unit134 for forming the second absorbent layer 62 of the absorbent core 14.

The first printing unit 132 may comprise a first auxiliary adhesiveapplicator 136 for applying an auxiliary adhesive to the substrate 64,which may be a nonwoven web, a first rotatable support roll 140 forreceiving the substrate 64, a first absorbent particulate polymer feeder(hopper) 142 for holding absorbent particulate polymer material 66, afirst printing roll 144 for transferring the absorbent particulatepolymer material 66 to the substrate 64, and a first thermoplasticadhesive material applicator 146 for applying the thermoplastic adhesivematerial 68 to the substrate 64 and the absorbent particulate polymer 66material thereon.

The second printing unit 134 may comprise a second auxiliary adhesiveapplicator 148 for applying an auxiliary adhesive to the secondsubstrate 72, a second rotatable support roll 152 for receiving thesecond substrate 72, a second absorbent particulate polymer feeder(hopper) 154 for holding the absorbent particulate polymer material 74,a second printing roll 156 for transferring the absorbent particulatepolymer material 74 from the hopper 154 to the second substrate 72, anda second thermoplastic adhesive material applicator 158 for applying thethermoplastic adhesive material 76 to the second substrate 72 and theabsorbent particulate polymer material 74 thereon.

The printing system 130 also includes a guide roller 160 for guiding theformed absorbent core from a nip 162 between the first and secondrotatable support rolls 140 and 152.

The first and second auxiliary applicators 136 and 148 and the first andsecond thermoplastic adhesive material applicators 146 and 158 may be anozzle system which can provide a relatively thin but wide curtain ofthermoplastic adhesive material.

Turning to FIG. 11, portions of the first hopper 142, first support roll140, and first printing roll 144 are illustrated. As also shown in FIG.12, the first rotatable support roll 140, which has the same structureas the second rotatable support roll 152, comprises a rotatable drum 164and a peripheral vented support grid 166 for receiving the firstsubstrate 64. The first vented support grid 166 extends in a crossdirection 167 a parallel to an axis of rotation of the first supportroll 140 and a machine direction 167 b substantially perpendicular tothe cross direction 167 a. The vented support grid 166 may include afirst plurality of cross bars 168 extending substantially parallel toand spaced from one another so as to form channels 170 extending betweenthe first plurality of cross bars 168. The first plurality of cross bars168 extend in the cross direction 167 a of the first vented support grid166 and are spaced from one another so that the channels 170 extendbetween the first plurality of cross bars 168 in the cross direction 167a of the first vented support grid 166. As shown in FIG. 13, the firstvented support grid 166 further comprises a plurality of spacers 172spaced from one another and extending between the first plurality ofcross bars 168 in the machine direction 167 b of the first ventedsupport grid 166. The first plurality of cross bars 168 each have asubstantially straight outwardly facing edge 174 extending acrosssubstantially the entire first vented support grid 166.

As also illustrated in FIG. 14, the first printing roll 144, which hasthe same structure as the second printing roll 156, comprises arotatable drum 180 and a plurality of absorbent particulate polymermaterial reservoirs 182 in a first peripheral surface 184 of the drum180. The reservoirs 182, best illustrated in FIG. 15, may have a varietyof shapes, including cylindrical, conical, or any other shape. FIG. 16and FIG. 17 demonstrate additional embodiments contemplated by theinvention. FIG. 16 shows a partial perspective view of an alternativeprinting roll showing absorbent particulate polymer material reservoirs.In this embodiment, the individual round holes in the print roll arereplaced with single or multiple slots. FIG. 17 demonstrates that theorientation of the bars in the laydown drum and/or the print roll can bedifferent from perpendicular to the MD, resulting in a pattern as shownin FIG. 17. Further, a combination of these embodiments is alsocontemplated by the invention.

The first peripheral surface 184 extends in a cross direction 185 aparallel to an axis of rotation of the first printing roll 144 and amachine direction 185 b substantially perpendicular to the crossdirection 185 a. The first plurality of reservoirs 182 in the firstperipheral surface 184 are arranged in an array 186 comprising rows 187extending substantially parallel to and spaced from one another. Thefirst support roll 140 and first printing roll 144 are arranged suchthat the first plurality of cross bars 168 are substantially parallel tothe rows 187 of the first plurality of reservoirs 182 in the firstperipheral surface 184, so that, when the first printing roll 144rotates, the first plurality of reservoirs 182 receive absorbentparticulate polymer material 66 from the first absorbent particulatepolymer material feeder 142 and deposit the absorbent particulatepolymer material 66 on the first substrate 64 in a first pattern 92 suchthat the absorbent particulate polymer material 66 collects in rows 94on the first substrate 64 formed between the first plurality of crossbars 168. The rows 187 of first plurality of reservoirs 182 extend inthe cross direction 185 a of the first peripheral surface 184 and arespaced from one another in the machine direction 185 b of the firstperipheral surface 184. The first support roll 140 and the firstprinting roll 144 are arranged such that the machine direction 167 b ofthe first vented support grid 166 is substantially parallel to themachine direction 185 b of the first peripheral surface 184 and thecross direction 167 a of the first vented support grid 166 issubstantially parallel to the cross direction 185 a of the firstperipheral surface 184.

According to a certain embodiment, the plurality of reservoirs 182 inthe first printing roll 144 each have a diameter 188 of about 3 to about8 mm or about 4 to about 6 mm, a spacing 190 in a cross direction 185 aof about 5.5 to about 10 mm or about 6 to about 8 mm or about 7.6 mmfrom reservoir center 192 to reservoir center 192, and a spacing 194 ina machine direction 185 b of about 8 to about 10 mm from reservoircenter 192 to reservoir center 192. According to a certain embodiment,the reservoirs 182 may have a depth of about 2 mm. The size of thereservoirs 182 may vary across the array 186 as desired to affect thebasis weight distribution of the absorbent particulate polymer material66 across the absorbent particulate polymer material area 114 of theabsorbent core 14.

In operation, the printing system 130 receives the first and secondsubstrate 64 and 72 into the first and second printing units 132 and134, respectively, the first substrate 64 is drawn by the rotating firstsupport roll 140 past the first auxiliary adhesive applicator 136 whichapplies the first auxiliary adhesive to the first substrate 64 in apattern such as described hereinabove. The first substrate 64 isdisposed on the first vented support grid 166 so that the firstsubstrate 64 directly contacts at least some of the first plurality ofcross bars 168 and, in a certain embodiment, the first substrate 64directly contacts the outwardly facing edges 174 of the first pluralityof cross bars 168 across substantially the entire length of the ventedsupport grid 166. According to a certain embodiment, about 8% of thearea of the first substrate 64 contacts the outwardly facing edges 174of the first plurality of cross bars 168.

A vacuum (not shown) within the first support roll 140 draws the firstsubstrate 64 against the vertical support grid 166 and holds the firstsubstrate 64 against the first support roll 140. This presents an unevensurface on the first substrate 64. Due to gravity, or by using thevacuum means, the substrate 64 will follow the contours of the unevensurface and thereby the substrate 64 will assume a mountain and valleyshape with the mountains corresponding to the first plurality of crossbars 168 and the valleys corresponding to the channels 170 therebetween.The absorbent particulate polymer material 66 may accumulate in thechannels 170 presented by the substrate 64 and form the rows 94 in theabsorbent particulate polymer material pattern 92. The first supportroll 140 then carries the first substrate 64 past the rotating firstprinting roll 144 which transfers the absorbent particulate polymermaterial 66 from the first hopper 142 to the first substrate 64 in thegrid pattern 92 which is best illustrated in FIGS. 5 and 6. The supportroll 140 then carries the printed first substrate 64 past thethermoplastic adhesive material applicator 136 which applies thethermoplastic adhesive material 68 to cover the absorbent particulatepolymer material 66 on the first substrate 64.

Hence, the uneven surface of the vented support grid 166 of the supportrolls 140 and 152 determines the distribution of absorbent particulatepolymeric material 66 and 74 throughout the absorbent core 14 andlikewise determines the pattern of junction areas 96.

Meanwhile, the second rotatable support roll draws the second substrate72 past the second auxiliary adhesive applicator 148 which applies anauxiliary adhesive to the second substrate 72 in a pattern such as isdescribed hereinabove. The second rotatable support roll 152 thencarries the second substrate 72 past the second printing roll 156 whichtransfers the absorbent particulate polymer material 74 from the secondhopper 154 to the second substrate 72 and deposits the absorbentparticulate polymer material 74 in the grid pattern 92 on the secondsubstrate 72 in the same manner as described with regard to the firstprinting unit 132 above. The second thermoplastic adhesive materialapplicator 158 then applies the thermoplastic adhesive material 76 tocover the absorbent particulate polymer material 74 on the secondsubstrate 72. The printed first and second substrates 64 and 72 thenpass through the nip 162 between the first and second support rolls 140and 152 for compressing the first absorbent layer 60 and secondabsorbent layer 62 together to form the absorbent core 14.

In an optional further process step a cover layer 70 may be placed uponthe substrates 64 and 72, the absorbent particulate polymer material 66and 74, and the thermoplastic adhesive material 68 and 76. In anotherembodiment, the cover layer 70 and the respective substrate 64 and 72may be provided from a unitary sheet of material. The placing of thecover layer 70 onto the respective substrate 64 and 72 may then involvethe folding of the unitary piece of material.

Embodiments described hereinabove may provide good uniformity ofabsorbent particulate polymer material distribution across the absorbentparticulate polymer material area 114 of the absorbent core 14 at lesserblow off air pressure and lesser vacuum applied by the support rolls 140and 152 and may reduce amount of absorbent particulate polymer materialthat needs to be recycled while maintaining or even enhancing wetimmobilization of the absorbent particulate polymer material. Inaddition, process control may be simplified because little or no offsetbetween the first and second absorbent layers 60 and 62 is required inthe cross direction. Furthermore, because the rows 94 of absorbentparticulate polymer material extend in a cross direction which issubstantially perpendicularly to the longitudinal axis 100 of theabsorbent core 14, the boundaries of the absorbent particulate polymermaterial pattern

The test method and apparatuses described below may be useful in testingembodiments of this invention:

Wet Immobilization Test Equipment

Graduated Cylinder

Stop watch (±0.1 sec)

Scissors

Light Box

Pen

Test solution: 0.90% saline solution at 37° C.

Metal ruler traceable to NIST, DIN, JIS or other comparable NationalStandard

PVC/metal dishes with a flat surface inside and a minimum length of thecore bag length (n) to be measured and a maximum length n+30 mm, widthof 105±5 mm, height of 30-80 mm or equivalent

Electronic Force Gauge (Range 0 to 50 Kg)

Wet Immobilization Impact Tester Equipment (WAIIT), Design packagenumber: BM-00112.59500-R01 available from T.M.G. Technisches BueroManfred Gruna

Facilities:

Standard laboratory conditions, temperature: 23° C.±2° C., relativehumidity: <55%

Sample Preparation

-   1. Open the product, topsheet side up.-   2. Unfold the diaper and cut the cuff elastics approximately every    2.5 cm to avoid chassis tension.-   3. For pull-up products open the side seams and remove the    waistbands.-   4. Lay the core bag flat and rectangular topsheet side up onto the    light box surface without any folds.-   5. Switch on the light box to clearly identify the absorbent core    outer edges.-   6. With a ruler, draw a line at the front and back absorbent core    outer edges.-   7. Measure the distance (A), between the two markers and divide the    value by 2, this will be calculated distance (B).-   8. Measure the calculated distance (B) from front marker towards the    middle of the core bag and mark it. At this marker draw a line in    the cross direction.

Test Procedure WAIIT Calibration:

-   1. Make sure that the sliding board is in the lower position. Open    the front door of the WAIIT tester and connect the force gauge hook    to the upper sample clamp of the WAIIT. Make sure that the clamp is    closed before connecting the spring-balance.-   2. Use both hands on the spring-balance to lift continuously and as    slowly as possible up the sliding board towards the upper position.    Record the average value (m₁) during the execution to the nearest    0.02 kg.-   3. Guide down the sliding board as slowly as possible to the lower    position and record the average value (m2) read off during execution    to the nearest 0.02 kg.-   4. Calculate and report the delta of m₁-m₂ to the nearest 0.01 kg.    If the delta is 0.6 kg±0.3 kg continue measurement. Otherwise, an    adjustment of the sliding board is necessary. Make sure that the    sliding board is in lower position and check the sliding path for    any contamination or damage. Check if the position of the sliding    board to the sliding path is correctly adjusted by shaking the    board. For easy gliding some clearance is needed. If not present,    readjust the system.

WAIIT Test Settings:

Drop height is 50 cm.

Diaper load (I_(D)) is 73% of the core capacity (cc); I_(D)=0.73×cc.

Core capacity (cc) is calculated as: cc=m_(SAP)×SAP_(GV), where m_(SAP)is the mass of superabsorbent polymer (SAP) present in the diaper andSAP_(GV) is the free swelling capacity of the superabsorbent polymer.Free swelling capacity of the superabsorbent polymer is determined withthe method described in WO 2006/062258. The mass of the superabsorbentpolymer present in the diaper is the average mass present in tenproducts.

Test Execution:

-   1. Reset the balance to zero (tare), put the dry core bag on the    balance, weigh and report it to the nearest 0.1 g.-   2. Measure the appropriate volume Saline (0.9% NaCl in deionized    water) with the graduated cylinder.-   3. Lay the core bag, topsheet side up, flat into the PVC dish. Pour    the saline evenly over the core bag.-   4. Take the PVC dish and hold it slanting in different directions,    to allow any free liquid to be absorbed. Products with    poly-backsheet need to be turned after a minimum waiting time of 2    minutes so that liquid under the backsheet can be absorbed. Wait for    10 minutes (+/−1 minute) to allow all saline to be absorbed. Some    drops may retain in the PVC dish. Use only the defined PVC/metal    dish to guarantee homogenous liquid distribution and less retained    liquid.-   5. Reset the balance to zero (tare), put the wet core bag on the    balance. Weigh and report it to the nearest 0.1 g. Fold the core bag    just once to make it fit on the balance. Check to see if the wet    core bag weight is out of limit (defined as “dry core bag    weight+diaper load±4 ml”). For example, 12 g dry core bag weight+150    ml load=162 g wet core bag weight. If the actual wet weight on the    scale is between 158 g and 166 g, the pad can be used for shaking.    Otherwise scrap the pad and use the next one.-   6. Take the loaded core bag and cut the pad along the marked line in    the cross direction.-   7. Put the back of the wet core bag onto the balance (m₁). Weigh and    report it to the nearest 0.1 g.-   8. Take the wet core and clamp the end seal side in the top clamp of    the sample holder of the WAIIT (open end of the core oriented down).    Next, clamp both sides of the core with the side clamps of the    sample holder making sure that the product is fixed to the sample    holder along the whole product length. Make sure not to clamp the    absorbent core, only the nonwoven; for some products this means    securing the product with only the barrier leg cuff.-   9. Lift up the sliding board to the upper position by using both    hands until the board is engaged.-   10. Close the safety front door and release the slide blade.-   11. Reset the balance to zero (tare), take the tested core bag out    of the WAIIT and put it on the balance (m₂). Report the weight to    the nearest 0.1 g.-   12. Repeat steps 7 to 11 with front of the wet core bag.

Reporting:

-   1. Record the dry core bag weight to the nearest 0.1 g.-   2. Record the wet weight before (m_(1 front/back)) and after    (m_(2 front/back)) testing, both to the nearest 0.1 g.-   3. Calculate and report the average weight loss (Δm) to the nearest    0.1 g: Δm=(m_(1front)+M_(1back))−(m_(2front)+m_(2back))-   4. Calculate and report the weight loss in percent to the nearest    1%, (Δm_(rel)):    (Δm_(rel))=(((m_(1front)+m_(1back))−(m_(2front)+m_(2back)))×100)/(mm_(1front)+m_(1back))-   5. Calculate and report Wet Immobilization (WI) as: WI=100%−Δm_(rel)

All patents and patent applications (including any patents which issuethereon) assigned to the Procter & Gamble Company referred to herein arehereby incorporated by reference to the extent that it is consistentherewith.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

All documents cited in the Detailed Description of the Invention are, inrelevant part, incorporated herein by reference; the citation of anydocument is not to be construed as an admission that it is prior artwith respect to the present invention. To the extent that any meaning ordefinition of a term in this document conflicts with any meaning ordefinition of the same term in a document incorporated by reference, themeaning or definition assigned to that term in this document shallgovern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

1. A method of making a disposable absorbent article comprising:providing a first support comprising a first grid including a firstplurality of cross bars extending substantially parallel to and spacedfrom one another so as to form channels extending between the firstplurality of cross bars; providing a first printing roll having a firstperipheral surface and a first plurality of reservoirs in the firstperipheral surface arranged in an array comprising rows extendingsubstantially parallel to and spaced from one another; depositingabsorbent particulate polymer material from the first plurality ofreservoirs onto a first substrate disposed on the first grid, while thefirst support and first printing roll are arranged such that the firstplurality of cross bars are substantially parallel to the rows of thefirst plurality of reservoirs, the absorbent particulate polymermaterial being deposited on the first substrate in a first pattern suchthat the absorbent particulate polymer material collects in rows on thefirst substrate formed between the first plurality of cross bars; anddepositing a thermoplastic adhesive material on the absorbentparticulate polymer material and the first substrate to cover theabsorbent particulate polymer material on the first substrate and form afirst absorbent layer.
 2. The method of claim 1 wherein: the first gridof the first support extends in a machine direction and a crossdirection substantially perpendicular to the machine direction and thefirst plurality of cross bars extend in the cross direction of the firstgrid and spaced from one another so that the channels extend between thefirst plurality of cross bars in the cross direction of the first grid;the peripheral surface of the first printing roll extends in a machinedirection and a cross direction substantially perpendicular to themachine direction, the rows of first plurality of reservoirs extend inthe cross direction of the first peripheral surface and are spaced fromone another in the machine direction of the first peripheral surface;and the step of depositing comprises depositing the absorbentparticulate polymer material from the first plurality of reservoirs ontothe first substrate disposed on the first grid while the first supportand first printing roll are arranged such that the machine direction ofthe first grid is substantially parallel to the machine direction of thefirst peripheral surface and the cross direction of the first grid issubstantially parallel to the cross direction of the first peripheralsurface.
 3. The method of claim 1 further comprising: providing a secondsupport comprising a second grid including a second plurality of crossbars extending substantially parallel to and spaced from one another soas to form channels extending between the second plurality of crossbars; providing a second printing roll having a second peripheralsurface and a second plurality of reservoirs in the second peripheralsurface arranged in an array comprising rows extending substantiallyparallel to and spaced from one another; depositing absorbentparticulate polymer material from the second plurality of reservoirsonto a second substrate disposed on the second grid, while the secondsupport and second printing roll are arranged such that the secondplurality of cross bars are substantially parallel to the rows of thesecond plurality of reservoirs, the absorbent particulate polymermaterial being deposited on the second substrate in a second patternsuch that the absorbent particulate polymer material collects in rows onthe second substrate formed between the second plurality of cross barsof the second support; depositing a thermoplastic adhesive material onthe absorbent particulate polymer material and the second substrate tocover the absorbent particulate polymer material on the second substrateand form a second absorbent layer; combining said first and secondabsorbent layers together in juxtaposed relation such that at least aportion of said thermoplastic adhesive material of said first absorbentlayer contacts at least a portion of the thermoplastic adhesive materialof said second absorbent layer, the absorbent particulate polymermaterial is disposed between the first and second substrates in anabsorbent particulate polymer material area, and the absorbentparticulate polymer material is substantially continuously distributedacross the absorbent particulate polymer material area.
 4. The method ofclaim 3 wherein: the first grid of the first support extends in amachine direction and a cross direction substantially perpendicular tothe machine direction and the first plurality of cross bars extend inthe cross direction of the first grid and spaced from one another sothat the channels extend between the first plurality of cross bars inthe cross direction of the first grid; the second grid of the secondsupport extends in a machine direction and a cross directionsubstantially perpendicular to the machine direction and the secondplurality of cross bars extend in the cross direction of the second gridand spaced from one another so that the channels extend between thesecond plurality of cross bars in the cross direction of the secondgrid; the peripheral surface of the first printing roll extends in amachine direction and a cross direction substantially perpendicular tothe machine direction, the rows of first plurality of reservoirs extendin the cross direction of the first peripheral surface and are spacedfrom one another in the machine direction of the first peripheralsurface; the peripheral surface of the second printing roll extends in amachine direction and a cross direction substantially perpendicular tothe machine direction, the rows of second plurality of reservoirs extendin the cross direction of the second peripheral surface and are spacedfrom one another in the machine direction of the second peripheralsurface; the step of depositing the absorbent particulate polymermaterial from the first plurality of reservoirs comprises depositing theabsorbent particulate polymer material from the first plurality ofreservoirs onto the first substrate disposed on the first grid while thefirst support and first printing roll are arranged such that the machinedirection of the first grid is substantially parallel to the machinedirection of the first peripheral surface and the cross direction of thefirst grid is substantially parallel to the cross direction of the firstperipheral surface; and the step of depositing the absorbent particulatepolymer material from the second plurality of reservoirs comprisesdepositing the absorbent particulate polymer material from the secondplurality of reservoirs onto the first substrate disposed on the secondgrid while the second support and second printing roll are arranged suchthat the machine direction of the second grid is substantially parallelto the machine direction of the second peripheral surface and the crossdirection of the second grid is substantially parallel to the crossdirection of the second peripheral surface.
 5. The method claim 1,wherein the rows of absorbent particulate polymer material on the firstsubstrate are separated by junction areas between the rows of absorbentparticulate polymer material.
 6. The method claim 3, wherein the rows ofabsorbent particulate polymer material on the first and secondsubstrates are separated by junction areas between the rows of absorbentparticulate polymer material and the step of combining comprisescombining said first and second absorbent layers together so that therows of absorbent particulate polymer material on the first substrateare disposed between and substantially parallel to rows of absorbentparticulate polymer material on the second substrate.
 7. The methodclaim 3, wherein the step of combining the first and second absorbentlayers comprises combining the first and second absorbent layerstogether such that the first and second patterns of absorbentparticulate polymer material are offset from one another in the machinedirection.
 8. The method claim 3, wherein: the first support is a firstsupport roll and the step of depositing the absorbent particulatepolymer material on the first substrate further comprises depositing theabsorbent particulate polymer material on the first substrate byrotating the first printing roll and rotating the first support roll;and the second support is a second support roll and the step ofdepositing the absorbent particulate polymer material on the secondsubstrate further comprises depositing the absorbent particulate polymermaterial on the second substrate by rotating the second printing rolland rotating the second support roll.
 9. The method claim 8, wherein:the first support roll is a first vacuum support roll and the step ofdepositing the absorbent particulate polymer material on the firstsubstrate further comprises holding the first substrate to the firstvacuum support roll with a vacuum; and the second support roll is asecond vacuum support roll and the step of depositing the absorbentparticulate polymer material on the second substrate further comprisesholding the second substrate to the second vacuum support roll with avacuum.
 10. The method claim 3, wherein the first and second pluralityof reservoirs are cylindrical or conical.
 11. The method claim 10,wherein the plurality of reservoirs in the first printing roll and theplurality of reservoirs each have a diameter of about 3 to about 8 mm, aspacing in a cross direction of about 5.5 to about 10 mm from reservoircenter to reservoir center, and a spacing in a machine direction ofabout 8 to about 10 mm from reservoir center to reservoir center. 12.The method claim 1, wherein the first plurality of cross bars each havea substantially straight outwardly facing edge extending acrosssubstantially the entire first grid.
 13. The method claim 1, wherein thefirst substrate is disposed on the first grid so that the firstsubstrate directly contacts at least some of the first plurality ofcross bars.
 14. The method claim 1, wherein the first grid furthercomprises a plurality of spacers spaced from one another and extendingbetween the first plurality of cross bars in the machine direction ofthe first support.
 15. An apparatus for making a disposable absorbentarticle comprising: a first absorbent particulate polymer materialfeeder; a first support comprising a first grid including a firstplurality of cross bars extending substantially parallel to and spacedfrom one another so as to form channels extending between the firstplurality of cross bars; a first printing roll for receiving absorbentparticulate polymer material from the first absorbent particulatepolymer material feeder having a first peripheral surface and a firstplurality of reservoirs in the first peripheral surface arranged in anarray comprising rows extending substantially parallel to and spacedfrom one another, the first support and first printing roll arrangedsuch that the first plurality of cross bars are substantially parallelto the rows of the first plurality of reservoirs in the first peripheralsurface, so that, when the first printing roll rotates, the firstplurality of reservoirs roll receive absorbent particulate polymermaterial from the first absorbent particulate polymer material feederand deposit the absorbent particulate polymer material on the firstsubstrate in a first pattern such that the absorbent particulate polymermaterial collects in rows on the first substrate formed between thefirst plurality of cross bars; and a first thermoplastic adhesivematerial applicator for applying thermoplastic adhesive materialapplicator on the absorbent particulate polymer material and the firstsubstrate to cover the absorbent particulate polymer material on thefirst substrate and form a first absorbent layer.
 16. The apparatus ofclaim 15 wherein: the first grid extends in a machine direction and across direction substantially perpendicular to the machine direction andthe first plurality of cross bars extend in the cross direction of thefirst grid and spaced from one another so that the channels extendbetween the first plurality of cross bars in the cross direction of thefirst grid; the first peripheral surface extends in a machine directionand a cross direction substantially perpendicular to the machinedirection, the rows of first plurality of reservoirs extend in the crossdirection of the first peripheral surface and are spaced from oneanother in the machine direction of the first peripheral surface; andthe first support and first printing roll are arranged such that themachine direction of the first grid is substantially parallel to themachine direction of the first peripheral surface and the crossdirection of the first grid is substantially parallel to the crossdirection of the first peripheral surface.
 17. The apparatus of claim 15further comprising: a second absorbent particulate polymer materialfeeder; a second support comprising a second grid including a secondplurality of cross bars extending substantially parallel to and spacedfrom one another so as to form channels extending between the secondplurality of cross bars; a second printing roll having a secondperipheral surface and a second plurality of reservoirs in the secondperipheral surface arranged in an array comprising rows extendingsubstantially parallel to and spaced from one another, the secondsupport and first printing roll arranged such that the second pluralityof cross bars are substantially parallel to the rows of the secondplurality of reservoirs in the second peripheral surface, so that, whenthe second printing roll rotates, the second plurality of reservoirsroll receive absorbent particulate polymer material from the secondabsorbent particulate polymer material feeder and deposit the absorbentparticulate polymer material on the second substrate in a second patternsuch that the absorbent particulate polymer material collects in rows onthe second substrate formed between the second plurality of cross bars;and a thermoplastic adhesive material applicator for depositing athermoplastic adhesive material on the absorbent particulate polymermaterial and the second substrate to cover the absorbent particulatepolymer material on the second substrate and form a second absorbentlayer, wherein the first and second supports are arranged for combiningsaid first and second absorbent layers together in juxtaposed relationsuch that at least a portion of said thermoplastic adhesive material ofsaid first absorbent layer contacts at least a portion of thethermoplastic adhesive material of said second absorbent layer, theabsorbent particulate polymer material is disposed between the first andsecond substrates in an absorbent particulate polymer material area, andthe absorbent particulate polymer material is substantially continuouslydistributed across the absorbent particulate polymer material area. 18.The apparatus of claim 17 wherein: the first grid of the first supportextends in a machine direction and a cross direction substantiallyperpendicular to the machine direction and the first plurality of crossbars extend in the cross direction of the first grid and spaced from oneanother so that the channels extend between the first plurality of crossbars in the cross direction of the first grid; the second grid of thesecond support extends in a machine direction and a cross directionsubstantially perpendicular to the machine direction and the secondplurality of cross bars extend in the cross direction of the second gridand spaced from one another so that the channels extend between thesecond plurality of cross bars in the cross direction of the secondgrid; the peripheral surface of the first printing roll extends in amachine direction and a cross direction substantially perpendicular tothe machine direction, the rows of first plurality of reservoirs extendin the cross direction of the first peripheral surface and are spacedfrom one another in the machine direction of the first peripheralsurface; the peripheral surface of the second printing roll extends in amachine direction and a cross direction substantially perpendicular tothe machine direction, the rows of second plurality of reservoirs extendin the cross direction of the second peripheral surface and are spacedfrom one another in the machine direction of the second peripheralsurface; the first support and first printing roll are arranged suchthat the machine direction of the first grid is substantially parallelto the machine direction of the first peripheral surface and the crossdirection of the first grid is substantially parallel to the crossdirection of the first peripheral surface; and the second support andsecond printing roll are arranged such that the machine direction of thesecond grid is substantially parallel to the machine direction of thesecond peripheral surface and the cross direction of the second grid issubstantially parallel to the cross direction of the second peripheralsurface.
 19. The apparatus claim 17, wherein the first and secondplurality of reservoirs are cylindrical or conical.
 20. The apparatusclaim 15, wherein the first plurality of cross bars each have asubstantially straight outwardly facing edge extending acrosssubstantially the entire first grid.